Obviously “naked” here means that nobody was wearing any gear, trinkets, rings, or weapons. As one would also likely expect, the raid group was made up primarily of casters save for some paladins for buffs and tanking purposes, but even they were naked as well, effectively punching a dragon so hard it got mad. There’s even a response from one of the raid members on the Reddit thread that explains just how a tank without any gear could hold aggro.
It’s almost 13 minutes of pure naked aggression and it’s embedded below for your viewing pleasure. And don’t worry, it’s SFW.